hw/i2c/core.c - qemu - Git at Google

 /*
  * QEMU I2C bus interface.
  *
  * Copyright (c) 2007 CodeSourcery.
  * Written by Paul Brook
  *
  * This code is licensed under the LGPL.
  */

 #include "qemu/osdep.h"
 #include "hw/i2c/i2c.h"
 #include "hw/qdev-properties.h"
 #include "migration/vmstate.h"
 #include "qapi/error.h"
 #include "qemu/module.h"
 #include "trace.h"

 #define I2C_BROADCAST 0x00

 static Property i2c_props[] = {
     DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
     DEFINE_PROP_END_OF_LIST(),
 };

 static const TypeInfo i2c_bus_info = {
     .name = TYPE_I2C_BUS,
     .parent = TYPE_BUS,
     .instance_size = sizeof(I2CBus),
 };

 static int i2c_bus_pre_save(void *opaque)
 {
     I2CBus *bus = opaque;

     bus->saved_address = -1;
     if (!QLIST_EMPTY(&bus->current_devs)) {
         if (!bus->broadcast) {
             bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;
         } else {
             bus->saved_address = I2C_BROADCAST;
         }
     }

     return 0;
 }

 static const VMStateDescription vmstate_i2c_bus = {
     .name = "i2c_bus",
     .version_id = 1,
     .minimum_version_id = 1,
     .pre_save = i2c_bus_pre_save,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(saved_address, I2CBus),
         VMSTATE_END_OF_LIST()
     }
 };

 /* Create a new I2C bus.  */
 I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
 {
     I2CBus *bus;

     bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
     QLIST_INIT(&bus->current_devs);
     vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_i2c_bus, bus);
     return bus;
 }

 void i2c_slave_set_address(I2CSlave *dev, uint8_t address)
 {
     dev->address = address;
 }

 /* Return nonzero if bus is busy.  */
 int i2c_bus_busy(I2CBus *bus)
 {
     return !QLIST_EMPTY(&bus->current_devs);
 }

 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
                   I2CNodeList *current_devs)
 {
     BusChild *kid;

     QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
         DeviceState *qdev = kid->child;
         I2CSlave *candidate = I2C_SLAVE(qdev);
         I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(candidate);

         if (sc->match_and_add(candidate, address, broadcast, current_devs)) {
             if (!broadcast) {
                 return true;
             }
         }
     }

     /*
      * If broadcast was true, and the list was full or empty, return true. If
      * broadcast was false, return false.
      */
     return broadcast;
 }

 /* TODO: Make this handle multiple masters.  */
 /*
  * Start or continue an i2c transaction.  When this is called for the
  * first time or after an i2c_end_transfer(), if it returns an error
  * the bus transaction is terminated (or really never started).  If
  * this is called after another i2c_start_transfer() without an
  * intervening i2c_end_transfer(), and it returns an error, the
  * transaction will not be terminated.  The caller must do it.
  *
  * This corresponds with the way real hardware works.  The SMBus
  * protocol uses a start transfer to switch from write to read mode
  * without releasing the bus.  If that fails, the bus is still
  * in a transaction.
  *
  * @event must be I2C_START_RECV or I2C_START_SEND.
  */
 static int i2c_do_start_transfer(I2CBus *bus, uint8_t address,
                                  enum i2c_event event)
 {
     I2CSlaveClass *sc;
     I2CNode *node;
     bool bus_scanned = false;

     if (address == I2C_BROADCAST) {
         /*
          * This is a broadcast, the current_devs will be all the devices of the
          * bus.
          */
         bus->broadcast = true;
     }

     /*
      * If there are already devices in the list, that means we are in
      * the middle of a transaction and we shouldn't rescan the bus.
      *
      * This happens with any SMBus transaction, even on a pure I2C
      * device.  The interface does a transaction start without
      * terminating the previous transaction.
      */
     if (QLIST_EMPTY(&bus->current_devs)) {
         /* Disregard whether devices were found. */
         (void)i2c_scan_bus(bus, address, bus->broadcast, &bus->current_devs);
         bus_scanned = true;
     }

     if (QLIST_EMPTY(&bus->current_devs)) {
         return 1;
     }

     QLIST_FOREACH(node, &bus->current_devs, next) {
         I2CSlave *s = node->elt;
         int rv;

         sc = I2C_SLAVE_GET_CLASS(s);
         /* If the bus is already busy, assume this is a repeated
            start condition.  */

         if (sc->event) {
             trace_i2c_event("start", s->address);
             rv = sc->event(s, event);
             if (rv && !bus->broadcast) {
                 if (bus_scanned) {
                     /* First call, terminate the transfer. */
                     i2c_end_transfer(bus);
                 }
                 return rv;
             }
         }
     }
     return 0;
 }

 int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
 {
     return i2c_do_start_transfer(bus, address, is_recv
                                                ? I2C_START_RECV
                                                : I2C_START_SEND);
 }

 int i2c_start_recv(I2CBus *bus, uint8_t address)
 {
     return i2c_do_start_transfer(bus, address, I2C_START_RECV);
 }

 int i2c_start_send(I2CBus *bus, uint8_t address)
 {
     return i2c_do_start_transfer(bus, address, I2C_START_SEND);
 }

 void i2c_end_transfer(I2CBus *bus)
 {
     I2CSlaveClass *sc;
     I2CNode *node, *next;

     QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
         I2CSlave *s = node->elt;
         sc = I2C_SLAVE_GET_CLASS(s);
         if (sc->event) {
             trace_i2c_event("finish", s->address);
             sc->event(s, I2C_FINISH);
         }
         QLIST_REMOVE(node, next);
         g_free(node);
     }
     bus->broadcast = false;
 }

 int i2c_send(I2CBus *bus, uint8_t data)
 {
     I2CSlaveClass *sc;
     I2CSlave *s;
     I2CNode *node;
     int ret = 0;

     QLIST_FOREACH(node, &bus->current_devs, next) {
         s = node->elt;
         sc = I2C_SLAVE_GET_CLASS(s);
         if (sc->send) {
             trace_i2c_send(s->address, data);
             ret = ret || sc->send(s, data);
         } else {
             ret = -1;
         }
     }

     return ret ? -1 : 0;
 }

 uint8_t i2c_recv(I2CBus *bus)
 {
     uint8_t data = 0xff;
     I2CSlaveClass *sc;
     I2CSlave *s;

     if (!QLIST_EMPTY(&bus->current_devs) && !bus->broadcast) {
         sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
         if (sc->recv) {
             s = QLIST_FIRST(&bus->current_devs)->elt;
             data = sc->recv(s);
             trace_i2c_recv(s->address, data);
         }
     }

     return data;
 }

 void i2c_nack(I2CBus *bus)
 {
     I2CSlaveClass *sc;
     I2CNode *node;

     if (QLIST_EMPTY(&bus->current_devs)) {
         return;
     }

     QLIST_FOREACH(node, &bus->current_devs, next) {
         sc = I2C_SLAVE_GET_CLASS(node->elt);
         if (sc->event) {
             trace_i2c_event("nack", node->elt->address);
             sc->event(node->elt, I2C_NACK);
         }
     }
 }

 static int i2c_slave_post_load(void *opaque, int version_id)
 {
     I2CSlave *dev = opaque;
     I2CBus *bus;
     I2CNode *node;

     bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
     if ((bus->saved_address == dev->address) ||
         (bus->saved_address == I2C_BROADCAST)) {
         node = g_malloc(sizeof(struct I2CNode));
         node->elt = dev;
         QLIST_INSERT_HEAD(&bus->current_devs, node, next);
     }
     return 0;
 }

 const VMStateDescription vmstate_i2c_slave = {
     .name = "I2CSlave",
     .version_id = 1,
     .minimum_version_id = 1,
     .post_load = i2c_slave_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(address, I2CSlave),
         VMSTATE_END_OF_LIST()
     }
 };

 I2CSlave *i2c_slave_new(const char *name, uint8_t addr)
 {
     DeviceState *dev;

     dev = qdev_new(name);
     qdev_prop_set_uint8(dev, "address", addr);
     return I2C_SLAVE(dev);
 }

 bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp)
 {
     return qdev_realize_and_unref(&dev->qdev, &bus->qbus, errp);
 }

 I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr)
 {
     I2CSlave *dev = i2c_slave_new(name, addr);

     i2c_slave_realize_and_unref(dev, bus, &error_abort);

     return dev;
 }

 static bool i2c_slave_match(I2CSlave *candidate, uint8_t address,
                             bool broadcast, I2CNodeList *current_devs)
 {
     if ((candidate->address == address) || (broadcast)) {
         I2CNode *node = g_malloc(sizeof(struct I2CNode));
         node->elt = candidate;
         QLIST_INSERT_HEAD(current_devs, node, next);
         return true;
     }

     /* Not found and not broadcast. */
     return false;
 }

 static void i2c_slave_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *k = DEVICE_CLASS(klass);
     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
     set_bit(DEVICE_CATEGORY_MISC, k->categories);
     k->bus_type = TYPE_I2C_BUS;
     device_class_set_props(k, i2c_props);
     sc->match_and_add = i2c_slave_match;
 }

 static const TypeInfo i2c_slave_type_info = {
     .name = TYPE_I2C_SLAVE,
     .parent = TYPE_DEVICE,
     .instance_size = sizeof(I2CSlave),
     .abstract = true,
     .class_size = sizeof(I2CSlaveClass),
     .class_init = i2c_slave_class_init,
 };

 static void i2c_slave_register_types(void)
 {
     type_register_static(&i2c_bus_info);
     type_register_static(&i2c_slave_type_info);
 }

 type_init(i2c_slave_register_types)
	/*
	* QEMU I2C bus interface.
	*
	* Copyright (c) 2007 CodeSourcery.
	* Written by Paul Brook
	*
	* This code is licensed under the LGPL.
	*/

	#include "qemu/osdep.h"
	#include "hw/i2c/i2c.h"
	#include "hw/qdev-properties.h"
	#include "migration/vmstate.h"
	#include "qapi/error.h"
	#include "qemu/module.h"
	#include "trace.h"

	#define I2C_BROADCAST 0x00

	static Property i2c_props[] = {
	DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
	DEFINE_PROP_END_OF_LIST(),
	};

	static const TypeInfo i2c_bus_info = {
	.name = TYPE_I2C_BUS,
	.parent = TYPE_BUS,
	.instance_size = sizeof(I2CBus),
	};

	static int i2c_bus_pre_save(void *opaque)
	{
	I2CBus *bus = opaque;

	bus->saved_address = -1;
	if (!QLIST_EMPTY(&bus->current_devs)) {
	if (!bus->broadcast) {
	bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;
	} else {
	bus->saved_address = I2C_BROADCAST;
	}
	}

	return 0;
	}

	static const VMStateDescription vmstate_i2c_bus = {
	.name = "i2c_bus",
	.version_id = 1,
	.minimum_version_id = 1,
	.pre_save = i2c_bus_pre_save,
	.fields = (VMStateField[]) {
	VMSTATE_UINT8(saved_address, I2CBus),
	VMSTATE_END_OF_LIST()
	}
	};

	/* Create a new I2C bus. */
	I2CBus i2c_init_bus(DeviceState parent, const char *name)
	{
	I2CBus *bus;

	bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
	QLIST_INIT(&bus->current_devs);
	vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_i2c_bus, bus);
	return bus;
	}

	void i2c_slave_set_address(I2CSlave *dev, uint8_t address)
	{
	dev->address = address;
	}

	/* Return nonzero if bus is busy. */
	int i2c_bus_busy(I2CBus *bus)
	{
	return !QLIST_EMPTY(&bus->current_devs);
	}

	bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
	I2CNodeList *current_devs)
	{
	BusChild *kid;

	QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
	DeviceState *qdev = kid->child;
	I2CSlave *candidate = I2C_SLAVE(qdev);
	I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(candidate);

	if (sc->match_and_add(candidate, address, broadcast, current_devs)) {
	if (!broadcast) {
	return true;
	}
	}
	}

	/*
	* If broadcast was true, and the list was full or empty, return true. If
	* broadcast was false, return false.
	*/
	return broadcast;
	}

	/* TODO: Make this handle multiple masters. */
	/*
	* Start or continue an i2c transaction. When this is called for the
	* first time or after an i2c_end_transfer(), if it returns an error
	* the bus transaction is terminated (or really never started). If
	* this is called after another i2c_start_transfer() without an
	* intervening i2c_end_transfer(), and it returns an error, the
	* transaction will not be terminated. The caller must do it.
	*
	* This corresponds with the way real hardware works. The SMBus
	* protocol uses a start transfer to switch from write to read mode
	* without releasing the bus. If that fails, the bus is still
	* in a transaction.
	*
	* @event must be I2C_START_RECV or I2C_START_SEND.
	*/
	static int i2c_do_start_transfer(I2CBus *bus, uint8_t address,
	enum i2c_event event)
	{
	I2CSlaveClass *sc;
	I2CNode *node;
	bool bus_scanned = false;

	if (address == I2C_BROADCAST) {
	/*
	* This is a broadcast, the current_devs will be all the devices of the
	* bus.
	*/
	bus->broadcast = true;
	}

	/*
	* If there are already devices in the list, that means we are in
	* the middle of a transaction and we shouldn't rescan the bus.
	*
	* This happens with any SMBus transaction, even on a pure I2C
	* device. The interface does a transaction start without
	* terminating the previous transaction.
	*/
	if (QLIST_EMPTY(&bus->current_devs)) {
	/* Disregard whether devices were found. */
	(void)i2c_scan_bus(bus, address, bus->broadcast, &bus->current_devs);
	bus_scanned = true;
	}

	if (QLIST_EMPTY(&bus->current_devs)) {
	return 1;
	}

	QLIST_FOREACH(node, &bus->current_devs, next) {
	I2CSlave *s = node->elt;
	int rv;

	sc = I2C_SLAVE_GET_CLASS(s);
	/* If the bus is already busy, assume this is a repeated
	start condition. */

	if (sc->event) {
	trace_i2c_event("start", s->address);
	rv = sc->event(s, event);
	if (rv && !bus->broadcast) {
	if (bus_scanned) {
	/* First call, terminate the transfer. */
	i2c_end_transfer(bus);
	}
	return rv;
	}
	}
	}
	return 0;
	}

	int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
	{
	return i2c_do_start_transfer(bus, address, is_recv
	? I2C_START_RECV
	: I2C_START_SEND);
	}

	int i2c_start_recv(I2CBus *bus, uint8_t address)
	{
	return i2c_do_start_transfer(bus, address, I2C_START_RECV);
	}

	int i2c_start_send(I2CBus *bus, uint8_t address)
	{
	return i2c_do_start_transfer(bus, address, I2C_START_SEND);
	}

	void i2c_end_transfer(I2CBus *bus)
	{
	I2CSlaveClass *sc;
	I2CNode node, next;

	QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
	I2CSlave *s = node->elt;
	sc = I2C_SLAVE_GET_CLASS(s);
	if (sc->event) {
	trace_i2c_event("finish", s->address);
	sc->event(s, I2C_FINISH);
	}
	QLIST_REMOVE(node, next);
	g_free(node);
	}
	bus->broadcast = false;
	}

	int i2c_send(I2CBus *bus, uint8_t data)
	{
	I2CSlaveClass *sc;
	I2CSlave *s;
	I2CNode *node;
	int ret = 0;

	QLIST_FOREACH(node, &bus->current_devs, next) {
	s = node->elt;
	sc = I2C_SLAVE_GET_CLASS(s);
	if (sc->send) {
	trace_i2c_send(s->address, data);
	ret = ret \|\| sc->send(s, data);
	} else {
	ret = -1;
	}
	}

	return ret ? -1 : 0;
	}

	uint8_t i2c_recv(I2CBus *bus)
	{
	uint8_t data = 0xff;
	I2CSlaveClass *sc;
	I2CSlave *s;

	if (!QLIST_EMPTY(&bus->current_devs) && !bus->broadcast) {
	sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
	if (sc->recv) {
	s = QLIST_FIRST(&bus->current_devs)->elt;
	data = sc->recv(s);
	trace_i2c_recv(s->address, data);
	}
	}

	return data;
	}

	void i2c_nack(I2CBus *bus)
	{
	I2CSlaveClass *sc;
	I2CNode *node;

	if (QLIST_EMPTY(&bus->current_devs)) {
	return;
	}

	QLIST_FOREACH(node, &bus->current_devs, next) {
	sc = I2C_SLAVE_GET_CLASS(node->elt);
	if (sc->event) {
	trace_i2c_event("nack", node->elt->address);
	sc->event(node->elt, I2C_NACK);
	}
	}
	}

	static int i2c_slave_post_load(void *opaque, int version_id)
	{
	I2CSlave *dev = opaque;
	I2CBus *bus;
	I2CNode *node;

	bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
	if ((bus->saved_address == dev->address) \|\|
	(bus->saved_address == I2C_BROADCAST)) {
	node = g_malloc(sizeof(struct I2CNode));
	node->elt = dev;
	QLIST_INSERT_HEAD(&bus->current_devs, node, next);
	}
	return 0;
	}

	const VMStateDescription vmstate_i2c_slave = {
	.name = "I2CSlave",
	.version_id = 1,
	.minimum_version_id = 1,
	.post_load = i2c_slave_post_load,
	.fields = (VMStateField[]) {
	VMSTATE_UINT8(address, I2CSlave),
	VMSTATE_END_OF_LIST()
	}
	};

	I2CSlave i2c_slave_new(const char name, uint8_t addr)
	{
	DeviceState *dev;

	dev = qdev_new(name);
	qdev_prop_set_uint8(dev, "address", addr);
	return I2C_SLAVE(dev);
	}

	bool i2c_slave_realize_and_unref(I2CSlave dev, I2CBus bus, Error **errp)
	{
	return qdev_realize_and_unref(&dev->qdev, &bus->qbus, errp);
	}

	I2CSlave i2c_slave_create_simple(I2CBus bus, const char *name, uint8_t addr)
	{
	I2CSlave *dev = i2c_slave_new(name, addr);

	i2c_slave_realize_and_unref(dev, bus, &error_abort);

	return dev;
	}

	static bool i2c_slave_match(I2CSlave *candidate, uint8_t address,
	bool broadcast, I2CNodeList *current_devs)
	{
	if ((candidate->address == address) \|\| (broadcast)) {
	I2CNode *node = g_malloc(sizeof(struct I2CNode));
	node->elt = candidate;
	QLIST_INSERT_HEAD(current_devs, node, next);
	return true;
	}

	/* Not found and not broadcast. */
	return false;
	}

	static void i2c_slave_class_init(ObjectClass klass, void data)
	{
	DeviceClass *k = DEVICE_CLASS(klass);
	I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
	set_bit(DEVICE_CATEGORY_MISC, k->categories);
	k->bus_type = TYPE_I2C_BUS;
	device_class_set_props(k, i2c_props);
	sc->match_and_add = i2c_slave_match;
	}

	static const TypeInfo i2c_slave_type_info = {
	.name = TYPE_I2C_SLAVE,
	.parent = TYPE_DEVICE,
	.instance_size = sizeof(I2CSlave),
	.abstract = true,
	.class_size = sizeof(I2CSlaveClass),
	.class_init = i2c_slave_class_init,
	};

	static void i2c_slave_register_types(void)
	{
	type_register_static(&i2c_bus_info);
	type_register_static(&i2c_slave_type_info);
	}

	type_init(i2c_slave_register_types)